Plant not eating, ph dropping, Aquafarm

[ukganjafarmer]

I have a single plant in a large aquafarm, under a 600w light, it is 3 weeks away from harvest.

The ph started dropping about a week ago, ec rising slightly, i have just been feeding at 0.8 ec for the last few days (water is 0.6 from the tap) and ph is still dropping.

Any ideas what is causing this problem?

 

[lost in a sea]

any sign of powdery mildew or mold on the plant or deep in the nugs?

 

[ukganjafarmer]

nope, buds look pretty gud

 

[Shafto]

Check for rot or slime in the root zone. Smell test works well.

Too bad you don't have lower EC water from the tap. I think you need to let it flush for 24 hours and then make a new batch of lower EC nutes.

They always slow down eating at the point you're at, but they shouldn't stop.

 

[medicalmj]

Aquafarm as in bunch of hydroton w recirc w pump and res beneath? Whens the last time you changed res? If it's been a couple weeks, (flush w something like florakleen if you haven't done yet) and change res solution. If its fresh change out could be the plant affecting PH or microbal growth, which can be good or bad, for me it's always been bad but I'm talking about going from 6.2 to 4.9 overnight. If it's just drifting a bit I'd flush w something like florakleen for couple hours then back to the nutes.

EDIT: Oh yeah, and what Shafto said. that bad slimy smell is BAD microbes. Been there and it always makes my PH drop like a rock. I've added H2O2 and the PH stabilizes as the microbes are all nuked.

 

[ukganjafarmer]

yes mj thats the one.

I change the water once a week but it usually drinks about 3-5 ltres per day so i have to top up, i have checked the roots and they look fine to me but yeh mine usually drops from 5.6 to 4.6 overnight.

 

[medicalmj]

What about brown/slimy/smelly roots? If you got rot there's a lot of debate about it (e.g. EWC tea v bleach or H2O2). Done both and not enough info to give my 2 cents.

I've come to blame the "sweeteners" for my problems. That is, adding directly to res per directions ignorant sales people.

I just started experimenting with adding EWC tea to the res to fight the rot with great results. Making the tea correctly is dicey however so be careful. Just got done looking at liquod from pump filter under scope and it'll freak ya out at first.

Q: whats your nute bill?

If I was to start a new room, I'd use nothing more than GH 3 part. And maybe PK booster and Rapid start. Keep it "sterile".

 

[resinryder]

yes mj thats the one.

I change the water once a week but it usually drinks about 3-5 ltres per day so i have to top up, i have checked the roots and they look fine to me but yeh mine usually drops from 5.6 to 4.6 overnight.

When was the last time you flushed it with a clearex type product? Sounds like a case of salt buildup causing your problem as has been mentioned above.

 

[jm420]

ec up ph down=to rich
ec down ph up = to lean

 

[medicalmj]

ec up ph down=to rich
ec down ph up = to lean

Astute observation! Why would say that happens? Buffers in ferts?

 

[jammie]

definately keep an eye on those roots. root rot will cause those symptoms, especially a rapid drop in ph. i do have to disagree with shafto. at 3 wks from harvest, mine are usually drinking a gallon a day and putting on lots of wt. thats why i think its a root problem

 

[jm420]

basicallyit works like this if your res is to lean the plant is taking more nutes than waterby taking those minerals causes the swing,to rich the plants taking more water than nutes wich causes the swing to go the other way.
This may not be the case in your situation if your tap water is .6 and your feeding at .8 says to me the plants are not getting the proper nutes.My tap water is about 100 ppms using lucas full streght brings me to about1200ppm


EC Hanna Eutech Truncheon CF
ms/cm 0.5 ppm 0.64 ppm 0.70 ppm 0
0.1 50 ppm 64 ppm 70 ppm 1
0.2 100 ppm 128 ppm 140 ppm 2
0.3 150 ppm 192 ppm 210 ppm 3
0.4 200 ppm 256 ppm 280 ppm 4
0.5 250 ppm 320 ppm 350 ppm 5
0.6 300 ppm 384 ppm 420 ppm 6
0.7 350 ppm 448 ppm 490 ppm 7
0.8 400 ppm 512 ppm 560 ppm 8
0.9 450 ppm 576 ppm 630 ppm 9
1.0 500 ppm 640 ppm 700 ppm 10
1.1 550 ppm 704 ppm 770 ppm 11
1.2 600 ppm 768 ppm 840 ppm 12
1.3 650 ppm 832 ppm 910 ppm 13
1.4 700 ppm 896 ppm 980 ppm 14
1.5 750 ppm 960 ppm 1050 ppm 15
1.6 800 ppm 1024 ppm 1120 ppm 16
1.7 850 ppm 1088 ppm 1190 ppm 17
1.8 900 ppm 1152 ppm 1260 ppm 18
1.9 950 ppm 1216 ppm 1330 ppm 19
2.0 1000 ppm 1280 ppm 1400 ppm 20
2.1 1050 ppm 1334 ppm 1470 ppm 21
2.2 1100 ppm 1408 ppm 1540 ppm 22
2.3 1150 ppm 1472 ppm 1610 ppm 23
2.4 1200 ppm 1536 ppm 1680 ppm 24
2.5 1250 ppm 1600 ppm 1750 ppm 25
2.6 1300 ppm 1664 ppm 1820 ppm 26
2.7 1350 ppm 1728 ppm 1890 ppm 27
2.8 1400 ppm 1792 ppm 1960 ppm 28
2.9 1450 ppm 1856 ppm 2030 ppm 29
3.0 1500 ppm 1920 ppm 2100 ppm 30
3.1 1550 ppm 1984 ppm 2170 ppm 31
3.2 1600 ppm 2048 ppm 2240 ppm 32
root problems would be real obvios at this point so theres somthing else going on.Another factor to consider is the smaller the res the harder iit is to keep PH in check

 

[Dark Helmet]

Astute observation! Why would say that happens? Buffers in ferts?

ec up ph down - using more water then nutes so hint at the ph going down and ec going up as water is being removed

 

[ukganjafarmer]

Ok

i have checked the roots before and they look and smell fine to me.

I have never flushed with anything except water, all i have on hand is 35% h202

 

[medicalmj]

If you're not adding bennies then you can try this, BUT if buds look good I'd be leary of chasing PH too much.

If you have 35% h2o2, should be technical or food grade, and you want to test the theory of microbe cause PH crash, add .25 oz/gal and check. I would add h2o2 to the water you'll be topping with, dont add directly to res.

And yes that's is 1/4 oz/gal of 35% h2o2, not the crap they sell at the drug store in brown bottle, its 3% and contains other stuff you don't want.

Again, I'd flush w above metioned first...

 

[ukganjafarmer]

can you give me that formula in mls/litres mate lol

 

[medicalmj]

can you give me that formula in mls/litres mate lol

as you can see the buds look ok but the leaves not looking to clever

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My pleasure! It's 1.95 ml/L or 2 ml/L.

 

[jm420]

No need for h202 if your roots are healthy and rez is clean .It dosnt flush the plant .For some reason peeps are leading you to a root issue ,When you have root rot you will know .
If you know your roots are good stop chasing your tail .

You must have some kind of lockout
Aquafarm and waterfarm are known to have ph spikes thats why I got rid of mine .Some peeps love thm.Search "water farm" there a whole thread on these types of systems.I bet you will find your answer there .
peace jm

 

[medicalmj]

Those buds look great and the yellow and purple leaves can be expected as the plant prepares to finish(die), but as JM420 observed may be a lockout as some look a little worse than others. But it won't hurt to try the theory.

 

[jm420]

Never mind, that plant is either a lot closer than you think or you have been having all kinds of issues for quite sometime and its way to late to start fucking with your res.you'l end up stresiing the shit out of her.